Yoda will most likely win in a fight against Darth Vader because he is more skilled with a lightsaber and has the experience and feats that allow him to trim whatever size and strength advantage Darth Vader has over him. In fact, Yoda nearly defeated Palpatine, something that Vader could never do.
While we never got to see Yoda vs. Darth Vader, it surely would have been a sight to behold. Had Yoda and Darth Vader fought each other both at full power, the fight arguably would have landed in Yoda's favor. Both are proficient with a lightsaber and with the Force, but Yoda might just be a little bit better.
again… One of the main reasons why Yoda would've won against Anakin is simply because he was far better trained than him. Yoda could see the moves his opponents were going to make before they made them; therefore, battling against Anakin would've put him at a far heavier advantage.
1 Luke Skywalker
Having faced his father once before, Luke was familiar with his tactics and used the force to gain an upper-hand. In Star Wars Canon, only Luke Skywalker can be acknowledged as the one who truly defeated Darth Vader.
Obi-Wan Kenobi soundly defeated Vader in Star Wars: Episode III - Revenge of the Sith and Obi-Wan Kenobi, and is easily one of the most powerful Jedi Vader ever faced. Vader and Obi-Wan were similar in swordsmanship and Force-sensitivity, but Vader's hatred of Obi-Wan often caused him to fight irrationally.
Some time later, he faced the Sith Lord Darth Vader. Infil'a put up a fierce fight against Vader, almost killing him by throwing the already damaged Sith Lord off of a cliff. Despite severe damage to his suit, Vader survived the fall, and repaired himself with parts from Infil'a's droid, Arex.
This might be a bit of a controversial pick at just number three, but Darth Vader, perhaps the best-known Dark Side user, is not the most powerful Sith ever. Born Anakin Skywalker, Vader became an extremely powerful Jedi Knight, one who was prophesized to be the "Chosen One" who would bring balance to the Force.
Vader, the only power who overrules him is papa Palpatine.
Yoda was tempted by the dark side on a few occasions throughout his life. If he fell to the Sith ways, he would've been more powerful than Palpatine.
Darth Vader's Insecurities are His Biggest Weaknesses
In the end, virtually all who have made the attempt to use Vader's cybernetic nature against him have ended up dead or defeated. The elite few who have had the upper hand, even before his conversion to mechanical monstrosity, have done so by dominating him mentally.
This ensured that the Sith could hone their skills in secret without fear of betrayal from rival Sith factions. More cunning and devious than all but the most attuned Force-sensitive beings, Darth Bane could more than likely defeat Yoda in a battle of both strength and wit.
The Sith Lord's powers were enough to overwhelm the Jedi and send him plummeting down to the depths of the senate chamber. Yet the battle wasn't a complete loss for Yoda, as Palpatine was just as overwhelmed and seemed to have taken the same level of beating. Yet still, Yoda saw the fight as a loss and took his leave.
There are certainly scenarios where Darth Vader would have the upper hand in a duel with Yoda, but in most cases, Yoda would be the more likely victor. Vader wields absurd levels of Force power during his dark side prime that would certainly rival Yoda's own abilities, but likely not exceed them.
Jedi Master Yoda is the most powerful of them all. This should come as no surprise, as he was the head of the Jedi Order in the prequels and was revered for his abilities during the original trilogy. Yoda's power is unmatched and was a real threat to Darth Vader and the Imperials.
For Now - Luke Skywalker. In Legends, Luke Skywalker was the undisputed most powerful Jedi to have ever lived in our knowledge, surpassing Yoda.
Yoda was a legendary member of the Jedi Council as a Grand Master of the Jedi Order and member of a mysterious species capable of living for centuries. He was stronger than most in a connection to the Force and though he was small in size, he'd been so powerful and wise having had trained Jedi for several centuries.
During the early days of the Clone Wars, Skywalker served as a Jedi General in the Grand Army of the Republic, commanding the clone troopers of the elite 501st Legion against the Confederacy of Independent Systems. After receiving his knighthood, Skywalker oversaw the Jedi training of his own apprentice, Ahsoka Tano.
As seen time and time again, the Sith Lord could easily cut down almost anyone who got in his way, and he rarely ever lost a fight. Yet at the end of Star Wars: Return of the Jedi, Luke is able to beat Vader to the ground with relative ease, and so what was different from all of Vader's previous fights?
It's a very common misconception. Darth Vader's “official” position was that of Imperial Enforcer. In terms of rank, practically everyone outranked him. However, his position came with a number of perks that allowed him to operate both within and outside of the Empire's regulations or militaristic chain of command.
Master Yoda has risen above all others to claim the top spot as the most powerful Jedi of all time and the true chosen one according to IGN's audience. He won pretty handily as well, as he was victorious in 89,756 of his 95,243 battles and had a win percentage of 94.2%.
Darth Sidious, also known as the Emperor and Supreme Chancellor Palpatine, is not just the evilest Sith in Star Wars (arguably in both canon and Legends) but the evilest villain overall, deemed so thanks to his irredeemable actions throughout the Skywalker saga and surrounding content.